Microsoft today re-released a security update that had crashed customers' PCs and crippled the machines with endless reboots, saying that the revised patch is now safe to install.

The revamped MS13-036 update -- first issued April 9, but pulled three days later from distribution -- "resolves issues some customers experienced," said Microsoft spokesman Dustin Childs in an email Tuesday.

"The new update, KB2840149, still addresses the Moderate security issue described in MS13-036, and should not cause these [rebooting] issues," Childs added in a post to the Microsoft Security Response Center blog.

Microsoft never clearly described the causes of the BSODs and endless reboots, saying at the time, "We've determined that the update, when paired with certain third-party software, can cause system errors." Childs today also declined to get into specifics, instead saying only that "some customers were having issues."

Customers and experts, however, pinned blame on combinations of the security update and "G-Buster," a browser security plug-in widely used in Brazil for online banking; and on the Microsoft patch and Kaspersky Lab security software.

In a support document, Microsoft had posted several error messages that were symptoms of the patch failure, and recommended that Windows 7 users uninstall the update.

The revised MS13-036 update has been restored to the Windows Update service, and will be downloaded and installed by machines with Automatic Updates enabled. Microsoft urged those who manually download patches to deploy the re-release at their earliest convenience.

Customers who prefer to retrieve updates manually can obtain the patch appropriate for their system -- Windows Vista, Windows 7, Windows Server 2008 or Windows Server 2008 R2 -- at Microsoft's Download Center by searching for "KB2840149" to filter the results.

Microsoft today re-released a patch that earlier this month sent some PCs into endless reboots or displayed the infamous "Blue Screen of Death."